Superconductivity at 2.5 K in the new transition-metal chalcogenide Ta₂PdSe₅

We report the synthesis and superconducting properties of a new transition-metal chalcogenide, Ta₂PdSe₅. Measurements of resistivity, magnetization, and specific heat reveal that Ta₂PdSe₅ is a bulk superconductor with . The zero-field electronic specific heat in the superconducting state can be fitted with a two-gap BCS model. The upper critical field H _c2 shows a linear temperature dependence, and the value of H _c2(0) is much higher than the estimated Pauli limiting field and orbital limiting field All these results of specific heat and upper critical field suggest that Ta₂PdSe₅ is a multi-band superconductor.